CAPE CANAVERAL — Confronted with orbiting junk again, NASA ordered the astronauts aboard the linked International Space Station and shuttle Discovery to move out of the way of a piece of debris Sunday.
Discovery's pilots fired their ship's thrusters to reorient the two spacecraft and thereby avoid a small piece from a 10-year-old Chinese satellite rocket motor that was due to pass uncomfortably close during today's planned space walk.
Mission Control said keeping the spacecraft in this position for about three hours — with Discovery's belly facing forward — would result in a slow, natural drag of about a foot per second, enough to get out of the way of the 4-inch piece of junk.
Space junk has been a recurring problem for the space station, especially recently. Last week, right before Discovery's arrival, the space station almost had to dodge a piece of junk from an old Soviet satellite, but it stayed at a safe distance.
The latest episode occurred as NASA scrambled to put together a spacewalking repair plan for a jammed equipment platform at the space station.
Today — on the third and final space walk of Discovery's mission — astronauts plan to return to an equipment storage shelf that jammed and could not be deployed Saturday.
Today's space walkers — former schoolteachers Joseph Acaba and Richard Arnold II — will use all their strength to get the shelf properly deployed. They will have pry bars and hammers, just in case. If nothing works, the jammed platform will simply be tied down with sturdier tethers.
Despite the recent incidents, Discovery's astronauts said they don't worry about space junk.
"We have enough other risks and worries to take on as we go outside," said Steven Swanson, who took part in the first two space walks.